Home directories are given automatically to everyone who has a CS account. The amount of disk space depends on your default group. If you need additional storage, see Requesting Storage Space.
How do I determine my disk quota/usage?
You can find your quota space usage by logging into the CS Guide. If you are not logged in, there will be a "User login" block on this page. Once logged in, you will see blocks showing your home directory and email usage/quota. You can also view your email quota in real-time (which includes any other data stored under Webmail). See the EMail Quota page for details.